This contract addresses the need for reliable and accurate biomarkers of alcohol consumption, initially in response to a National Institute on Alcohol Abuse and Alcoholism (NIAAA)-initiated Small Business Innovation Research (SBIR) contract topic on Biomarkers for Alcohol-induced Disorders. The goals of this contract are to advance the usefulness of phosphatidylethanol (PEth), an alcohol metabolite, as a clinical biomarker of alcohol consumption, by designing an antibody-based method of quantitation that is cheaper and more accessible to small hospitals and clinics than currently used chromatographic/ spectrophotometric methods. This contract is a continuation of a Phase II SBIR contract with Echelon Biosciences, Inc. It was awarded under SBIR solicitation PHS-2008-1, Topic 031. This effort is deemed to be non-severable.